ethernet: increase timeout to deflake tests am: 227dfb5ad0 am: 9a11120c27

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/18728707

Change-Id: I1d94a52835fc56e858848afa4cebc2c67c39a544
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>